Escalator



Nov. 17, 1931. F. G. HEALY 1,832,204

ESCALATOR Filed April 14, 1928 2 Sheets-Sheet l F. a. HEALY Nov. 17,1931;

ESCALATOR Filed April 14, 1928 2 Sheets-Sheet 2 Patented Nov. 17, 1931 1UNITED STATES.

rRANcIs e. HEALY, or ARLINGTON, MASSACHUSETTS ESCALAT OR Applicationfile'd April 14, 1928. Seria1 No. 269,92 0. H c Fig. 4, a sectional;detail on the line 44 This invention relates to a safety device forinclined conveyers and particularly for escalators.

.7 The invention has for an object to provide anovel, efiicient,relatively inexpensive safety device for inclined conveyers, and partcularly for an escalator of the ascending type,

which is capable of operating more rapidly in the event of breakage ofthe conveyor than any of the other types of safety devices which haveheretofore been proposed for usein con nection wlth such conveyers andknown to me.

To this end, the safety device includes a control switch andmechanismfor operating the same actuated, in the event of breakage ofthe conveyer, by movementof a portion of the conveyer in its normaldirection of travel. v V

When embodied in an inclined escalator, the control switch is arrangedto be operated, in the event of chain-breakage,by the lower lap of theescalator chain. a

The control switch is preferably arranged to control the motor circuitand the application of brakes to the motor armature, and in the event ofbreakage of the escalator chain, the sudden decrease in the load uponthe motor operates to speed the motor up, with the result that a portionof the escalator chain is moved at a much higher speed inthe directionof its normal travel and provision is made for utilizing the slackdeveloped by such movement to actuate the control switch and open themotor circuit and also permit the application of the brakes to thearmature. I I 1 These and other, features of this invention will bepointed out in the claims'at the end of this specification. I y Fig. 1is a side elevation of a suificie'nt portion of an ascending escalatorequipped with the present safety device to enable 'theinven tion to beunderstood; 7 5

Fig. 2, a wiring diagram illustrative of the control switch andconnections to the motor; Fig.3, an enlargeddetail inside elevation ofthe lower portion of the escalator chain illustrating the operation of.the control switch by the slack developedin the'lower lap of the chain;and

of Fig. 3. v p

While t-hedifi'erent features of the present invention are applicahle todi-fierentforins of inclinedconveyers in which itgis desirable tocontrol'the'descent. ofthe conveyor in thei event of breakagethereof,fthe invention is prlmarily designed for use-1n connection withtheescalator's now commonly used to... convey passengers fromdiiferent'levels in subways, elevated structures, stores and the like.As is well known such escalators are,

providedwith an inclined, endless escalator chain running sprockets.

As herein illustrated, the invention is 7 shown and willbedescr'ibed asembodied in a safety device in which provision is made for over upperand lower opening the motor circuit and for applying brakes tothearmature-of the motor in the event ofbreakage of the upper lap of thechain. -Nevertheless iffound desirable theinvention may bejembodied insafety devices for actuating othercontrolling devices for the escalatoror other conveyer. I

Referring now tothe drawings, which .illus trate the invention asembodied in a safety device applied to. an escalator of the standardascending type at present generally used, 1.0 represents an endlesschain adapted to travel over an upper sprocket 12 and a lower sprocket13, both the sprockets 12 and 13 being suitably journaled in a framework.14 by which the escalator is supported. .The'chain 10 has operativelyconnected therewith tread members 15 upon whichthe passengers stand. Theescalator is driven by an electric motor represented diagrammatically at16 in ,Fig; 2, and which is connected through suitable gearing,notshown, to the upper sprocket 12 to drive the same. The constructionand operation of the escalator per so may comprise that illustrated inthe patent to Seeberger No. 1,025,316,?or that illustrated in the patentment of the lower half of the upper length or made for operating thesafety device by the lap of the chain in the event of chain-breakage,and in practice some lapse of time occurred between the chain-breakageand the actual operation of the safety devices.

In the illustrated escalator, provision is accumulation of slack in thelower lap of the escalatorchainin the event of chain-breakage, and ithas been found that a safety device actuated in this manner is renderedoperative much more quickly than any of the prior safety devices knownto me, for the reason that upon chain-breakage the motor speeds up, dueto the sudden decrease in load thereon, and operates to cause the lowerlap of the chain to pile up or to develop. slack in the lower endthereof in a rapid and positive manner.

In the present safety device in which provision is made for operating itby the weight of the slack portion of the "chain thus developed, it hasbeen found that the motor circuit can be opened before reverse motionhas been imparted to thelower section of the upper lap of the chain. Inother-words. upon chain-breakage in an escalator equipped with thepresentsafety device, it is possible to stop the motor beforethe lowersection of the upper lap of the chain moves any appreciable amount.

. The present safety device in addition avoids the liability of themotor becoming damaged and of the operating mechanism becoming damaged,and insures the stopping of the motor and the application of brakes tothe armature thereof in a minimum time after chain-breakage hasoccurred.

As herein shown, the safety. device includes a circuit-controllingswitch, indicated generally at 40 and including a pair of contacts 42,44 and a movable switch member 46, which is normally held in engagementwith the contacts 42, 44 by a spring 48 surrounding a stud 49 andbearingupon the under side of the switch member 46.

The stud 49 is carried by a plate 50 pivoted at 51 to be capable ofbeing swung from the position illustrated in Figs. 1 and 2 to thatillustrated-in Fig. 3 The plate 50 isinaintainedin a raised positionby'the engage ment' with the underside of the plate of a pin 52securedin a bracket'54 attached to a hinged section 56 forming a partof. the escalator track. The hinged section 56 constitutes the actuatingmember for the switch, and in the illustrated escalator a pair of suchhinged sections 56 are provided, which are connected by a cross or tiebar '5 8 to move as a unit (see Fig. 4). The hinged sections 56 aremaintained in a normal or raised position, forming the lower end of theescalator track upon which the rollers 60 for the escalator chainrun, bya'spring 64 interposed between a plate 65 on a bolt 66, pivoted to theunder portion of the cross piece 58, and

a supporting cross plate or bar secured to the under side of theescalator guards 72.

The normal or raised position of the hinged sections 56 may beadjustably determined by suitable nuts 7 4 upon the bolts 66.

In the illustrated escalator, the control switch 40 is arranged, whenthrown, to open the motor circuit, and by reference to Fig. 2, it willbe observed that when the circuit is opened at the terminals 42, 44, theholding coil 94 of apotential switch 92 is deenergized, thus permittingthe switch 92 to open the motor circuit and deenergize the solenoid 100,permitting the springs 102 to cause the application of thefbrakes 103 tothe drum 104 on the motor shaft.

As above stated the present invention insures the control of theescalator in the event of. chain-breakage in a rapid, highly ellicientand positive manner, and in practice it has been found that the controlswitch 40 was thrown in less than a second after chainbreakage and thatthe motor was stopped within a period of a second and a half.

The hinged section 56 of the track is preferably made adjustable withrelation to the path of the chain 10, so that asthe chain becomes wornin service 'and the slack therein is taken up in the usual or normalmanner, the hinged section 56 maythen be adjusted to meet the newcondition oft-he escalator chain, and. yet have the hinged section inoperative relation to the switch 40. I

To this end the pin 52 isv adjustable in a curved slot 152 in thebracket 54, the slot 152 having the pivot 153' for the hinged section 56as a center. 7 i

The hinged section 56 of the track is pivoted to the lower end of astationary section 154 secured to the framework 14. V

As represented in Figs. 1 and 2', the pin 52 is at the lowermost end ofthe curved slot 152, as the hinged section 56 is in its uppermostposition and the chain is in its initially adjusted position.

hen the chain. becomes worn in service and it is adjusted to a newposition, a nut (not shown) on the pin 52 is backed off, and the hingedsection 56 is lowered by adjusting the nuts 74, and when the hingedsection 56 is properly positioned with relationto the new path of thechain, the nut on the pin 52 is turned up to fasten the latter to thebracket 54.

In this adjusted position of the hinged section 56. the lower end of thecurved slot 152 will be below the pin 52, which in this adjust edposition engages the plate 50 to hold the motor switch 40 closed.

While the preferred embodiment of the invention has been illustrated anddescribeduit will be understood that the invention may be embodiedinother forms within the scope of the following claims. Y

Having thus described the invention what is claimed is:

1. An escalator having, in combination, an inclined endless conveyer, anescalator track for the lower lap of the conveyer having a hingedsection capable of downward movement, a spring for maintaining saidsection in a normal position, and a motor control switch operativelyconnected with said hinged section to be actuated upon depression of thesame by weight of the lower lap of the conveyer in the event of chainbreakage and independently of reverse movement of the upper lap of saidconvey-er.

2. An escalator having, in combination, an endless conveyer chain, upperand lower sprockets for driving the same, a track to support the lowerlap of said chain having a stationary upper section and a movable lowersection pivoted to the stationary section,

means for yieldingly supporting the free end of said movable section, amotor control switch operatively connected with said movable tracksection to be maintained closed while the movable section is in itselevated position and to permit said switch to be opened by the weightof the lower lap of the chain moving the pivoted track section downwardand independently of the reverse movement of the upper lap of saidchain. 7

3. An escalator having, in combination, an endless conveyer chain, upperand lower sprockets for driving the same, a track to support the lowerlap of said chain having a hinged section provided with a bracket, a

spring to elevate said hingedsection, a con-' trol switch. and a devicecarried by said bracket and co-operating with said control switch tonormally close the same and to permit said switch to be opened by thelower lap of the chain under abnormal conditions of the latter andindependently of the reverse movement of the upper lap of said chain.

4. An escalator having, in combination, an

endless conveyer chain, upper and lower sprockets for driving the same,a track to support the lower lap of said chain having a hinged sectionprovided with a bracket, a spring to elevate said hinged section, acontrol switch, and a device carried by said bracket and adjustablethereon, said device co-operating with saidcontrol switch to normallyclose the same and to permit said switch to be opened by the lower lapof the chain In testimony whereof, I have signed my name tothisspecification. I

FRANCIS G. HEALY.

